Erythrina alkaloids from leaves of Erythrina arborescens

Continued interest in Erythrina alkaloids resulted in the isolation of 38 alkaloids including 7 undescribed ones from the leaves of Erythrina arborescens Roxburgh. Among the new compounds, erythrivarines H-I were two dimeric alkaloids, while others were Erythrina alkaloid glucosides. Dimeric Erythrina alkaloids and monomers, turcomanidine and isoboldine, showed medium xanthine oxidase inhibition.     

Transgenic Artemisia dubia WALL showed altered phytochemistry and pharmacology

The rol genes have been shown to enhance the production of secondary metabolites in plants. This report examines the effect of trans-genes (rol ABC) on possible high production of biologically important phytochemicals and enhanced pharmacological activities. Three transgenic lines (1, 2 and 3) of Artemisia dubia WALL (transformed with Agrobacterium tumefaciens harboring rol ABC genes) were subjected to phytochemical analysis and pharmacological studies. A great variation in phytochemistry and the pharmacological activities was observed not only between the transgenic and non-transgenic control plants but also among the transgenic lines itself. Comparative chemical profile obtained via HPLC, TLC and spectrophotometry showed high degree of variations in the quantity of phytochemicals. An increased production of total flavonoids (71.1% in transgenic line 2) and total phenolics (110.8% in transgenic line 1), increase in caffeic acid and catechin and a decrease in gallic acid content in the extracts of transformed plants compared to the untransformed control plants was decreased. In case of pharmacological activities, moderate to high level increase in antimicrobial (antibacterial and antifungal) activities, cytotoxicity (14.1%), antitumor (29%) and antioxidant activities (23.9%) was observed (in transgenic line 2). In general all the three transgenic lines under study showed improvement in their pharmacological activities in the order of transgenic line 2 > 1 > 3 > control. The implication of these findings will help to meet the increasing demand of pharmacologically important compounds.     

The ethnobotanical,phytochemistry and pharmacological activities of Psidium guajava L.

Psidium guajava L., commonly known as guava is an important tropical food plant with diverse medicinal values. In traditional medicine, it is used in the treatment of various diseases such as diarrhoea, diabetes, rheumatism, ulcers, malaria, cough, and bacterial infections. The aim of this review is to provide up-to-date information on the ethnomedicinal uses, bioactive compounds, and pharmacological activities of P. guajava with greater emphasis on its therapeutic potentials. The bioactive constituents extracted from P. guajava include phytochemicals (gallic acid, casuariin, catechin, chlorogenic acid, rutin, vanillic acid, quercetin, syringic acid, kaempferol, apigenin, cinnamic acid, luteolin, quercetin-3-O-α-L-arabinopyranoside, morin, ellagic acid, guaijaverin, pedunculoside, asiastic acid, ursolic acid, oleanolic acid, methyl gallate and epicatechin) and essential oils (limonene, trans-caryophyllene, α-humulene, γ-muurolene, selinene, caryophyllene oxide, bisabolol, isocaryophyllene, δ-cadinene, α-copaene, α-cedrene, β-eudesmol, α-pinene, β-pinene, β-myrcene, linalool, α-terpineol and eucalyptol). In vitro and in vivo studies demonstrated that P. guajava possesses pharmacological activities such as antidiabetic, antidiarrhoeal, hepatoprotective, anticancer, antioxidant, anti-inflammatory, antiestrogenic, and antibacterial activities which support its traditional uses. The exhibited pharmacological activities reported may be attributed to the numerous bioactive compounds present in different parts of P. guajava. Based on the beneficial effects of P. guajava as well as its bioactive constituents, it can be exploited in the development of pharmaceutical products and functional foods. However, there is a need for comprehensive studies in clinical trials to establish the safe doses and efficacy of P. guajava for the treatment of several diseases.     

Lignans and Alkaloids from Haplophyllum suaveolens

Summary.  A new lignan of the dibenzylbutyrolactone type, haplotonin, was isolated from the aerial parts of Haplophyllum suaveolens together with five known compounds-the alkaloids flindersine, 6-methoxyflindersine, N-acetoxymethylflindersine, and evoxine and the lignan 4-acetyldiphyllin. This is the first report on the occurrence of N-acetoxymethylflindersine in the genus Haplophyllum and on 6-methoxyflindersine and 4-acetyldiphyllin as constituents of the investigated species. Received August 10, 1999. Accepted (revised) October 12, 1999     

Chemical profiling of Aristolochia tagala Cham. leaf extracts by GC-MS analysis and evaluation of its antibacterial activity

Aristolochia tagala Cham. (Aristolochiaceae) is an underexplored medicinal plant traditionally used to treat snakebites, stomachaches, and poisonous bites. In this study, chemical profiling of the petroleum ether, chloroform, ethyl acetate, methanol, and hydro-alcoholic extracts of the plant was investigated by gas chromatography-mass spectrometry. The antibacterial activity of the plant was tested against ten bacterial strains using the agar disc diffusion and microdilution method. In total, forty two compounds were identified from the extracts with neophytadiene, palmitic acid, phytol, trans-δ9-octadecenoic acid, phytyl palmitate, phytyl tetradecanoate, ergost-5-en-3-ol, (3beta,24r)-,z,z-8,10-hexadecadien-1-ol, stigmasterol, and tetrapentacontane as major phytoconstituents. The hydro-alcoholic extract possessed maximum total phenolics (52.58 ± 06 mg GAE/g), total flavonoids (48.66 ± 91 QRE/g), total flavanols (67.20 ± 64 QRE/g) and vitamin E content (31.26 ± 0.05 mg ATE/g). For antibacterial activity, hydro-alcoholic extract of Aristolochia tagala effectively controlled the growth of bacterial strains such as Proteus valgaris (26.3 mm) and Pseudomonas aeruginosa (19.33 mm) and the same extract showed notable minimum inhibitory concentration (MIC) against the growth of bacteria like Escherichia coli (10.93 μg/ml) and Enterobacter aerogenes (43.7 μg/ml). It was determined that, hydro-alcoholic and methanolic extracts Aristolochia tagala leaf found to have a number of bioactive compounds with significant antibacterial activity against the pathogenic bacteria. Further investigations are necessary to isolate and characterize bioactives and to evaluate its therapeutic potential.     

Alkaloid-rich plant Tylophora indica; current trends in isolation strategies,chemical profiling and medicinal applications

Tylophora indica, a threatened medicinal plant of family Asclepiadaceae, grows profoundly in Asia, Africa, Australia, Oceanic Islands, Ceylon, Malay island, and Borneo. The plant is a twinning herb that is excessively used in folk medicine as a substitute of ipecac, an expectorant. Different parts of the plant are accredited for the anti-asthmatic, antibacterial, anti–psoriasis, antimicrobial, antiulcer, antiallergic, antidiarrhoeal, hypolipidemic, and anxiolytic properties. Antidiabetic, hepatoprotective, antiangiogenic, anti-tumor, antioxidant, anticonvulsant, anti-rheumatic, and diuretic activities are also attributed to the magnificent medicinal plant owing to the occurrence of various active phytochemicals such as alkaloids, saponins, phytosterols, tannins, and primary metabolites. The plant has been exploited by the ethnic people due to the immense medicinal importance, leading to the endangerment of the plant species. The review brings to light the important pharmacological attributes, folk medicinal uses, and biotechnological approaches that must be followed to save the plant from extinction.     

Metabolic variations in seaweed,Sargassum polycystum samples subjected to different drying methods via 1H NMR-based metabolomics and their bioactivity in diverse solvent extracts

Seaweeds are known as excellent sources of unique bioactive metabolites. In the present study, proton nuclear magnetic resonance (¹H NMR) combined with principal component analysis (PCA) was used to distinguish the metabolic variations in Brown seaweed, Sargassum polycystum treated under different drying processes. The study also evaluated the phytochemistry, antioxidant, and antimicrobial effects of S. polycystum extracted in different solvents. Mutually under the different drying processes investigated, a total of 12 metabolites were identified from ¹H NMR analysis. Freeze drying emerged as the most efficient process that preserved most of the potentially beneficial metabolites in the samples. The results of the qualitative phytochemical screening of differentially dried S. polycystum extracts revealed the presence of various secondary metabolites. The 70% ethanol extract exhibited the highest total phenolic (627 ± 50.81 mg GAE/100 g dried samples) and also displayed the highest DPPH scavenging activity (61.4 ± 0.171%) at the highest concentration (3 mg ml⁻¹) tested. Methanol extract on the other hand contained the highest total antioxidant capacity (121.00 ± 0.003 mmol/g) followed by 70% ethanol extract (120.00 ± 0.001 mmol/g) at concentration of 1.25 mg/mL. The 70% ethanol extract also showed inhibition zone towards all bacteria samples tested compared to others solvent extracts. Based on these results, the identification of metabolites variations using PCA is considered as very useful procedure as a basis to recommend the most efficient processing (drying) method. The potential utilization of the tested Brown seaweed S. polycystum species as a source of antioxidants and antibacterial agents were also highlighted. The commercial cultivation of the species therefore, needs to be encouraged and promoted.     

基于一流本科教学的植物化学类课程体系构建探索

目前全国有442所高校设置有应用化学专业,如何使该专业办出特色并具有广阔需求前景是我们亟待解决的关键问题。屠呦呦因青蒿素获得诺贝尔化学奖彰显出"植物化学成分研究"的重要性,与此同时,人类医疗与健康对植物中活性成分需求也日益增长。经过18年的教学实践与探索,紧密结合学校"双一流"农业大学使命,我们找到了以植物化学为支撑来培育应用化学长线专业在我校的一流优势与特色问题,以植物化学成为国家级精品课程的标志性成就,形成了紧扣"双一流建设"国家重大需求的西北农林科技大学应用化学专业本科教育新体系。